[Richard L]

Yes, the FDC hi-jack the guage to display FIDC for diagnostic purpose. Normally, it displays water flow.

You only scale the SC after you have done all the tests and jets.

1. I suggest you cut x1 and solder link the x1.5 to amplify the IDC signal a tad. "underside of the board" since you are not using 100% fuel injection.

2. If you are only using 1x 1mm jet againist a 4000cc/min fuel capacity, you are well under jetted. You be running two jets.

100% water ........ 10-15% to fuel
M50:W50 ........... 15-20% to fuel
100% methanol ........ 20-25% to fuel
(these are the simple rules that work well)

3. If you can not using boost as a trigger, you don't need to tap into the MSP sensor at all. I have always stress that IDC trigger is a more accurate indication of enigne load then boost. Boost is different at different engine load or gear.

4. I think you should wire the red to a known switched 12V source, active only at the pre-crank position. It will be less confusing and reliable. Injector (+) can sometimes be spiky and noisy. Some cars still have resistor packs (no good for the HFS3).

You are nearly there. What car do you have?